Engine starting control system

ABSTRACT

A control system for an engine having a starting motor, a battery, an ignition switch for connecting the battery to the engine, and a fuel valve for controlling the flow of fuel to the engine. The ignition switch is closed a predetermined number of times to crank the engine and start it, and means are provided for terminating the flow of fuel to the engine if it has not been started by the successive crankings. The system also includes means for terminating closure of the ignition switch when the engine begins to run and means which prevent closure of the ignition switch for a predetermined time if the engine is coasting to a halt when an engine start command is applied to the system. A predetermined time after the engine has been started, the engine oil pressure is monitored and low oil pressure causes the fuel valve to be closed, thereby stopping the engine. The water temperature and speed of the engine also operate switches which close the fuel valve if either is excessive.

Przywozny 1 Feb. 11, 1975 [5 ENGINE STARTING CONTROL SYSTEM [75] Inventor: Walter C. Przywozny, Whippany,

[73] Assignee: Automatic Switch Company,

- Florham Park, NJ.

[22] Filed: Nov. 12, 1973 [21] Appl. No.: 415,267

[52] US. Cl.....; 307/10 R, 307/67, 318/481, 290/38 R [51] Int. Cl. F02n ll/00 [58] Field of Search 307/64, 66, 67, 68, 10 R, 307/10 BP; 340/52 R;'3l8/481; 290/37, 38 R; 123/179; 317/9, 21

[56] References Cited UNITED STATES PATENTS 3,514,621 5/1970 Farmer et a1. 290/38 R Primary ExaminerHerman J. Hohauser Attorney, Agent, or FirmBreitenfeld & Levine [57] ABSTRACT A control system for an engine having a starting motor, a battery, an ignition switch for connecting the battery to the engine, and a fuel valve for controlling the flow of fuel to the engine. The ignition switch is closed a predetermined number of times to crank the engine and start it, and means are provided for terminating the flow of fuel to the engine if it has not been started by the successive crankings. The system also includes means for terminating closure of the ignition switch when the engine begins to run and means which prevent closure of the ignition switch for a predetermined time if the engine is coasting to a halt when an engine start command is applied to the system. A predetermined time after the engine has been started, the engine oil pressure is monitored and low oil pressure causes the fuel valve to be closed, thereby stopping the engine. The water temperature and speed of the engine also operate switches which close the fuel valve if either is excessive.

6 Claims, 6 Drawing Figures ma l 22 SAGE D SKI/mi trig AC POWER SIM/ M6 FUEL PATENTEB FEB! 1 I975 SHEET 1 BF 5 1 ENGINE STARTING CONTROL SYSTEM flow to the engine is controlled by an accelerator pedal,

and by depressing the pedal on starting the operator assures an adequate supply of fuel to the engine. The average automobile also has a set of gages or lights which provide information concerning critical engine conditions such as water temperature and oil pressure. The operator, by observing these gages, can determine engine malfunction and in response thereto can stop the engine before serious damage occurs. Thus, in effect, the operator serves as a starting control system since he provides all the basic logic necessary to start and stop the engine under various engine conditions.

Although operator control is suitable for automobile engines, there are many systems, such as standby emergency electric power systems, where this type of control is impractical and expensive. For these applications, automatic starting-control systems have been devised which perform necessary engine control functions without operator attendance. Since the mind of an operator can perform many control functions, automatic controlsystems attempting to duplicate these functions have been either very complex or have only included the minimum functions required to control a prime mover. For example, control systems utilizing relays for all switching functions are. physically large, heavy, consume excessive power, and are subject to failure due to intermittent contacts.

Accordingly, it is an object ofthe present invention to provide an improved prime mover starting control systemqiwhich utilizes electromagnetic relays only where the voltage required toperform a control function would place in jeopardy solid state switching circuits capable of providing the same function.

' It is another object of the present invention to provide a prime mover starting control system which provides at most a fixed number of cranks to the prime mover and if the prime mover fails to start terminates provide a cranking circuit which is inhibited for a predetermined time when the prime mover is coasting to a halt.

The foregoing and other objects and features of the invention are incorporated in the example now to be described with reference to the accompanying drawings, in which:

FIG. 1 shows ablock diagram of a starting control system for an internal combustion engine, according to the invention; 1

FIG. 2 is a schematic diagram of the part of the control system used for cranking the engine and for charging thesystem battery;

, FIG. 3 is a schematic diagram of the part of the control system used for timing the cranking of the engine;

FIG. 4 is a schematic diagram of the part of the control system used for controlling the supply of fuel to the engine;

FIG. 5 is a schematic diagram of the part of the control system used for detecting malfunctions of the engine and providing engine shutdown commands; and

FIG. 6 is a block and schematic diagram of the counter shown in FIG. 3.

An engine starting control system chosen to illustrate the present invention, is shown schematically in FIG. 1. In general, the system includes means for cranking an engine; means for controlling'the crank time and the number of cranks provided; means for detecting engine faults; and means for controlling the fuel valve of the engine.

As shown in FIG. 1, the system is powered by a battery 10 which is connected, via a fuse 11, to a terminal 12 of a two-position toggle switch 13, the other terminal 14 of the toggle switch being open circuited. The movable contact terminal 15 of switch 13 is connected, as more fully discussed below, to relay contacts of the system and to a circuit 25 for detecting engine faults. In addition, terminal 15 is connected to the movable contact terminal 16 of another two position toggle switch 17. The terminals 18 and 19 of switch 17 are connected to terminals 20 and 21, respectively, and terminals 20 and 21 are connected to a shorting switch 22 which may be located remotely with respect to the rest of the system. Terminal 21 is also coupled to a cir-. cuit 26 for timing the crank drive, to relays 27 and 118, and. a fuel valve control circuit 28. Thus, when the movable contact of switch 13 connects'terminals l2 and 15 and when the movable contact of switch 17 connects terminals 16 and 18, closure of the shorting switch 22 supplies voltage to the crank. timing circuit 26, the.relays 27 and 118, and the fuel control circuit 28. As describedbelow, the voltage supplied causes the system to start an engine (not shown). It should be noted that with terminals'l5 and 12 connected the shorting switch 22 may be bypassed to start the engine by throwing switch 17 so-that terminal 16;is connected to terminal 19.

The means for cranking the engine include a crank drive circuit 30, the relay 27, and a magnetic ignition switch 31 which typically is mounted on the-engine; Re-

ferring to FlGSpl and 2, terminal 21 is connected-t0 one end of a resistor 32 and the other end of resistor 32 is connected'to line 33. Capacitor 34 couples line 33 of transistor 37 is connected to ground, and the base of transistor 37 is connected to ground, through resistor 38, and to the emitter of transistor 36. Thebase of transistor 36 is connected to ground through resistor 39, and through resistor 40 to the crank timer 26. Resistors 38, 39, and 40 bias the transistors 36 and 37 and in combination with the transistors provide a current drive circuit for the coil 35. Diode 41 shunts coil 35 to protect the transistors 36 and 37.

' As shown in FIG. 2, contacts and 46 of relay 27 are connected, normally open contact 47 is connected to terminal 15, and normally open contact 48 is connected to one end of engine-mounted magnetic ignition switch 31 and to'the cathode of a diode 50. The other end of the ignition switch 31 and the other end of the diode 50 are connected to ground. Thus, actuation of the relay 27 operates the ignition switch 31, thereby connecting the battery 10 to the starting motor 51 to crank the engine. The normally closed contact 52 of the'relay 27 is connected to a battery charger 55, and normally closed contact 53 is connected to battery 10. However, the battery charger is disconnected during engine cranking.

FIG. 3 shows schematically the circuitry for controlling the crank drive circuit 30. In FIG. 3, it may be seen that line 33 is connected to the emitter of a PNP transistor 56, that the base of transistor 56 is-connected to ground through resistor 57, and that the collector of transistor 56 is connected to one end of a resistor 58. The other end of resistor 58 is connected, via line 59, to one end of a grounded zener diode 60. When voltage is applied to terminal 21, to start the engine, transistor 56. is turned on, resistor 58 limits the flow of current, and zener diode 60 maintains a regulated voltage on line 59. Line 59 is connected to one end of resistor 61 and the other end of this resistor is connected to the gateof a unijunction transistor 62 and to ground via resistor 63. Thus, resistors 61 and 63 provide a voltage divider which sets the firing voltage of unijunction transistor 62. Line 59 is also connected to oneend of a resistor 64 whose other end is connected to the unijunction transistor 62 and to a grounded capacitor 65. Transistor 62 is connected by line 66 to a ripple counter 67 and tea grounded resistor 68. As a result, when voltage is applied to terminal 21 capacitor charges through resistor 64 until thevoltage on the capacitor'65 exceeds the firing voltage established by resistors 61 and 63. When the firing voltage is exceeded transistor 62 fires, thereby applying a pulse to the counter 67. This pulse presets the ripple counter in the proper mode toinsure a predetermined count. of 4 (assuming-it is desired to crank theengine 4 times before cranking, is discontinued) or any other desired number.

In this-example, ripple counter 67 is provided by interconnecting a pairfof CD 4013AE RCA integrated circuits 70 and 71 '(see' FIG. 6). integrated circuit 70 includes a pair of flip-flops 72 and 73 and integrated circuit 71 includes a pair of flip-flops 74 and 75. As is typical in this type of counter, the set inputs of flipflops 72-75 are connected to-each other and to a pulse source such as is present on line 66. The Q terminal of flip-flop 72 is connected to the'clock input of flip-flop 73; the Q terminal of flip-flop 73. is connected, via line 76, to the clock terminal of flip-flop 74; the Q terminal of'flip-flo'p 74 is connected via line 77, to the clock terminal of flip-flop 75; and the Q terminalv of flip-flop 75 is connected to a line 78. As more fully described be low, a crank timing circuit applies pulses, via line 79 to sistors 81, 82, 84 provide a voltage divider which sets the firing voltage for transistor and supplies current to the base of transistor 83. The cathode of unijunction transistor 80 is connected to ground through current limiting resistor 85 and the anode is connected to line 59 through resistor 86 and to ground through capacitor 87. The emitter of transistor 83 is grounded and the collector is connected through resistor 88 to line 59 and by line 79 to the clock input of the counter 67. Thus, when voltage is applied on line 59 alow voltage is provided on line 66 and this voltage prevents the counter 67 from counting until the unijunction transistor is fired by the rising voltage on capacitor 87, thereby turning transistor 83 off. Transistor 83 will remain off until the dischargecurrent from capacitor 87 falls below the holding current of unijunction transistor 80. Once below the holding current, unijunction transistor 85 will turn offand permit its gate voltage to rise, thereby turning transistor 83 back on. Thus, it will be seen that the charge and discharge times of capacitor 87 determines the rate at which pulses are provided to counter 67 via line 79.

Referring to FIGS. 3 and 6, lines 76, 77, and 78 are connected to a NOR gate and line 76 is connected to the crank drive 30. The NOR gate includes a NPN transistor 90 whose base is connected through resistor 91 the delivery of fuel to the engine. It may beseen that The other end of the resistor 95 is connected by line 96 to fault circuit 25 and to ground through resistor 97. As a result, a'binary '1 state on any one of the lines 76, 77, or 78 causes transistor 90 to conduct, thereby providing a low voltage to' the ,fault circuit 25. As more fully described below, this inhibits an. engine cranking and after 4 timing pulses have been provided, via line 76, binary Os are provided on lines 76, 77, and 7-8, and transistor 90 turnsoff. 'As are'sult, engine cranking 'is terminated. v

Referring to FIGS. 1 and 3, an engine speed switch 100, typically mounted on the engine, is connected in series between terminal 12 and an end of resistor 101.,

The other end of resistor 101. is connected to the anode of diode 102. The cathode ofdiode' 102 is connected to ground by capacitor 103 and tothe anode of diode 104. The cathode of diode 104 is connected to ground through resistor 105 and to the base of transistor 106.

The emitter of transistor 106 is connected to ground and the collector is connected to one end of resistor 107'. The other end of resistor 107 is connected to line 33 through a resistor 108 and to the base of transistor 109. The emitter of transistor 109 is connected to line 33 and the collector is connected to the base of transis-.

tor 56 and resistor 57. When the cranking results in starting the engine, switch closes and current is delivered via resistor 101 and diodes. 102 and 104 to the base of transistor 106. This currentturns transistor 106 on, thereby causing current to flow from line 33 through the emitter to base junction of transistor 109, through resistor 107 and through transistor 106 to ground. As a result, transistor 109 turns on and'transistor 56 is turned off. When transistor 56 is turned off the voltage on line59 drops and engine cranking is inhibited. From the foregoing, it may be seenthat cranking turns the engine on, and when the engine starts running cranking is automatically terminated.

' With the engine running capacitor 103 charges. When the engine is signaled to stop it will coast at a predetermined speed switch 100 opens. When switch 100 opens capacitor 103 discharges through constant current diode 104 and transistor 106. As a result, transistor 56 remains off for a fixed period of time after the switch 100 opens and cranking is inhibited during this period.

Referring to FIGS. 1 and 4, fuel flow to the engine is controlled by a fuel valve 121 and a fuel valve control circuit 28. In this embodiment the fuel valve control circuit includes a resistor 111 connected at one end to line 33. The other end of resistor ll1 is connected, via line 112, to the anode of a diode 113, connected to fault circuitb25, and to one end of resistor 114. The other end of resistor 114 is connectedv to the base of a transistor 116 and to ground via resistor 1 15. The emitter of transistor 116 is grounded and its collector is connected by the coil 117 ofa relay 118 (see FIG. 1)

to line 33. To protect the coil 117 a diode 119 is connected thereto in parallel. A normally open contact 120 of relay 118 is connected to terminal and the associated arm 123 is connected to ground by a fuel valve 121 and a diode 122 which protects the fuel valve 121. With this arrangement when a signal from the fault circuit turns transistor 116 on, the current flowing through the coil 117 actuates the relay 118, thereby causing the actuation of the fuel valve 121.

' In general, the fault circuit 25 monitors engine mounted safety switches in order to stop the engine in the event of an engine malfunction. Four basic engine faults are monitored and these are: low oil pressure, high water temperature, over-speed, and overcrank.

, Referring to FIG. 1, the fault circuitry 25 is arranged such that two conditions must be met before oil pres sure can be sensed. The first-condition is that the speed switch 100 must be closed, indicating that the engine is running, and the second condition is that the speed switch be closed-for at least a time sufficient to allow the oil pressure. in the engine to build up. Further, the fault circuitry prevents an oil pressurefailure indication if any one of the other three faults occur. When an engine is shut down due to a fault condition, there is a resultant loss of oil pressure that could give a false indication. Therefore, the low oil pressure fault circuit is locked out when one of the other faults occurs. A detailed description of the fault circuit 25 follows.

Referring to FIGS. 1 and 5, terminal 15 is connected, through the low pressure oil switch 130, to one end of a resistor 131 and the other end of resistor 131 is connected through resistor 132 to'the gate of silicon controlled rectifier 133. Thus, when switch 130 is closed, corresponding to low oil pressure, voltage is applied to the gate. The switch 130 is also connected to one end of a bias resistor 134 whose other end is connected to the base of a transistor 135 and to ground via a bias re- FIGS. 3 and 5, the speed switch 100 is connected by line 138 to the fault circuit 25. In the fault circuit, line 138 is connected to ground through resistor 139, to-the cathode ofa diode 140 and to one end of a resistor 141.

The anode of diode and the other end of resistor 141 are connected to ground by a capacitor 142 and to zener diode 143. Thus, when the engine is started switch 100 closes and capacitor 142 charges. After a predetermined time, the voltage across the capacitor charges to a level which is sufficient to cause the zener diode 143 to conduct. The diode 143 is connected to ground by resistor 144 and to the base of transistor 145. The emitter of transistor 145 is grounded and its collector is connected to resistors 134 and 136 and the base of transistor 135. Thus, when zener diode 143 conducts, transistor 145 is turned on and transistor 135 is turned off, thereby permitting current to flow into the gate of control rectifier 133 if the low pressure oil switch is closed. The anode of the rectifier 133 is connected through resistor 146 and indicator lamp 147 to terminal 12, through transient suppressing capacitor 148 to ground, and through resistor 149 to a test point 150. The cathode is connected by a resistor 151 to the base of transistor 152 and the gate is connected to the base of transistor 152 by a capacitor 153. The base of transistor 152' is grounded via a resistor 158, the emitter is grounded, and the collector is connected through resistor 154 and diode 155 to line 156 which is connected to the base-of transistor 109 in the crank timer 26. Thus, when control rectifier 133 is turned on lamp 147 lights and transistor 152 turns on, thereby turning transistor 109 off and terminating cranking. The collector of transistor 152 is also connected to diode 113 (see FIG. 5) in the fault, circuit 25, and via the coil 161 of relay (see FIG. 1) to terminal 12. Diode 162 is shunted across coil 161 to protect transistor 152. As a result, when transistor 152 is turned on, the fuel valve isclosed and the relay 161 is activated The contacts (not shown) of relay 161 are used to provide an exter-- nal alarm control. g

The overspeed switch 165 and the watertemperature switch 166 are separately connected by voltage dividterminates cranking and the delivery of fuel to the engine. Similarly, line 96 from the crank timer 26 is connected to a control rectifier circuit 173, also connected to the base of transistor 152. control rectifier circuits 169, 170, 173 provide test points 174, 175, 176, respectively, which are similar to test point 150.

From the foregoing, it may be seen that the control system described provides within a predetermined period a fixed number of cranks to an engine and that if the engine is not started by the cranks, a fault condition is indicated. Since oil pressure in an engine is normally low until after the engine has started to run, a test for oil pressure is delayed a fixed amount of time and thereafter the oil pressure in the engine is monitored. Malfunctions in either speed or water pressure are also monitored. When an engine malfunction is sensed, the flow of fuel to'the engine is terminated and the engine is shut down. An indication of the particular engine fault detected is provided by the lamps associated with the control rectifier circuits.

It is to be understood that the description herein of a preferred embodiment according to the invention is set forth as an example thereof and is not to be construed or interpreted as a limiation on the claims which follow and define the invention.

what is claimed is:

l. A control system for an engine having a starting 7 motor, a battery, and an ignition switch for connecting the battery to the motor to crank the engine, the system comprising:

a. means for providing a start signal, b. a solid state counter for providing a plurality of periodic pulses in response to a single start signal,

c. means responsive to said pulses for closing and opening the'ignition switch a plurality of times so as to energize and deenergize the starting motor to periodically crank the engine, and

d. means responsive to a predetermined number of pulses from said counter for terminating the output of further pulses from said counter and hence for terminating engine cranking.

2. A control system as defined in claim 1 including means responsive to a predetermined minimum speed of the. started engine for terminating the output of further pulses from said counter and hence for terminating engine cranking.

3. A control system as defined in claim 1 including means for producing a signal when the speed of the engine falls below a predetermined value, and means responsive to said signal-producing means for introducing a time delay between the occurrance of a start sig nal and the output of pulses from saidcounter, so that the engine will not be cranked while it is coasting to a stop.

4. A control system as defined in claim 1 wherein said counter is a four flip-flop ripple counter, and said means responsive to a predetermined number of pulses from the counter is a NOR gate having three inputs, each of the inputs being connected to the Q output of a different one of the last three flip-flops of the counter.

5. A control system as defined in claim 1 including means for controlling the flow of fuel to the engine, means responsive to oil pressure in the engine below a predetermined value for causing said control means to discontinue supplying fuel to the engine, means for producing a signal when the speed of the started-engine rises above a predetermined value, and means for introducing a time delay between the occurrance of said speed signal and the time said '0 pressure responsive means can cause said fuel-controlling means to discontinue supplying fuel to the engine.

6. A control system as defined in claim 1 including means for charging the battery, and means for disconnecting the battery from said battery charging means when the ignition switch is closed.

. l= l l= 

1. A control system for an engine having a starting motor, a battery, and an ignition switch for connecting the battery to the motor to crank the engine, the system comprising: a. means for providing a start signal, b. a solid state counter for providing a plurality of periodic pulses in response to a single start signal, c. means responsive to said pulses for closing and opening the ignition switch a plurality of times so as to energize and deenergize the starting motor to periodically crank the engine, and d. means responsive to a predetermined number of pulses from said counter for terminating the output of further pulses from said counter and hence for terminating engine cranking.
 2. A control system as defined in claim 1 including means responsive to a predetermined minimum speed of the started engine for terminating the output of further pulses from said counter and hence for terminating engine cranking.
 3. A control system as defined in claim 1 including means for producing a signal when the speed of the engine falls below a predetermined value, and means responsive to said signal-producing means for introducing a time delay between the occurrance of a start signal and the output of pulses from said counter, so that the engine will not be cranked while it is cOasting to a stop.
 4. A control system as defined in claim 1 wherein said counter is a four flip-flop ripple counter, and said means responsive to a predetermined number of pulses from the counter is a NOR gate having three inputs, each of the inputs being connected to the Q output of a different one of the last three flip-flops of the counter.
 5. A control system as defined in claim 1 including means for controlling the flow of fuel to the engine, means responsive to oil pressure in the engine below a predetermined value for causing said control means to discontinue supplying fuel to the engine, means for producing a signal when the speed of the started engine rises above a predetermined value, and means for introducing a time delay between the occurrance of said speed signal and the time said oil pressure responsive means can cause said fuel-controlling means to discontinue supplying fuel to the engine.
 6. A control system as defined in claim 1 including means for charging the battery, and means for disconnecting the battery from said battery charging means when the ignition switch is closed. 